Firebase createAuth credentials aren't working with ng-model scope variables

I'm using AngularFire in an Ionic project for the first time. I followed the example in the docs on the firebase website for Auth with email and password.For some reason my $scope values from ng-model aren't binding properly.

angular.module('starter')
.controller('RegisterController', ['Auth', '$scope', function(Auth, $scope) {

  $scope.createUser = function() {
    $scope.message = null;
    $scope.error = null;

    Auth.$createUser({
      email: $scope.email,
      password: $scope.password
    })
    .then(function(userData) {
      $scope.message = "User created: ";
    })
    .catch(function(error) {
      $scope.error = error;
    });
  };

}]);

If I replace the $scope.email and $scope.password` with a hardcoded email and password it works. Here is the template with the email and password model data.

<ion-view view-title='Register A New Account' hide-back-button="false">
  <ion-content class='padding'>

    <div class="list list-inset">

      <label class='item item-input'>
       <span class='input-label'>Email</span>
        <input type="text" placeholder='example@email.com' ng-model="email">
      </label>

      <label class='item item-input'>
       <span class='input-label'>Password</span>
        <input type="password" placeholder='' ng-model='password'>
      </label>

      <label class='item item-input'>
       <span class='input-label'>Cell Phone</span>
        <input type="tel" placeholder='316-333-3333'>
      </label>

      <label class='item item-input'>
       <span class='input-label'>Date of Birth</span>
        <input type="date">
      </label>

      <label class='item item-input'>
        <span class='input-label'>City</span>
        <input type="number" placeholder='Wichita'>
      </label>

      <label class='item item-input'>
        <span class='input-label'>State</span>
        <input type="number" placeholder='Kansas'>
      </label>

      <label class='item item-input'>
        <span class='input-label'>Zipcode</span>
        <input type="number" placeholder='67208'>
      </label>



    </div>
    <ion-checkbox>
      I agree to terms and conditions
    </ion-checkbox>
    <button class='button button-block button-calm' ng-click='createUser()'>Login</button>

      <p ng-if='message'>Message: {{message}}</p>
      <p ng-if='error'>Error: {{error}}</p>
  </ion-content>
 </ion-view>

Is my $scope value set wrong or is there something about the createAuth method that I am missing?